On the rate adaptation and scheduling design of downlink multi-user, multiple-antenna base station with imperfect CSIT

In this paper, we investigate the downlink rate adaptation and scheduling design in multiuser multiple-input single-output (MISO) systems with imperfect channel state information at the transmitter (CSIT). We shall propose a systematic design framework to address the rate adaptation and multi-user scheduling combined design based on information theoretical framework. We assume time division duplex (TDD) systems with quasi-static fading channels where packet outage is an important concern with imperfect CSIT. A lower bound on the mutual information of a MISO link in the presence of CSI errors is derived. Based on this lower bound, we present a closed form expression for the average goodput of each user, with packet outage taken into account. Numerical results demonstrate that, by considering the statistic of CSIT errors into the design, the proposed schemes provide significant goodput enhancement